462 lines
12 KiB
C
462 lines
12 KiB
C
/*
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* net/dccp/options.c
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*
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* An implementation of the DCCP protocol
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* Copyright (c) 2005 Aristeu Sergio Rozanski Filho <aris@cathedrallabs.org>
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* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
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* Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/config.h>
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#include <linux/dccp.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/skbuff.h>
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#include "ackvec.h"
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#include "ccid.h"
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#include "dccp.h"
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/* stores the default values for new connection. may be changed with sysctl */
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static const struct dccp_options dccpo_default_values = {
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.dccpo_sequence_window = DCCPF_INITIAL_SEQUENCE_WINDOW,
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.dccpo_ccid = DCCPF_INITIAL_CCID,
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.dccpo_send_ack_vector = DCCPF_INITIAL_SEND_ACK_VECTOR,
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.dccpo_send_ndp_count = DCCPF_INITIAL_SEND_NDP_COUNT,
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};
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void dccp_options_init(struct dccp_options *dccpo)
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{
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memcpy(dccpo, &dccpo_default_values, sizeof(*dccpo));
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}
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static u32 dccp_decode_value_var(const unsigned char *bf, const u8 len)
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{
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u32 value = 0;
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if (len > 3)
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value += *bf++ << 24;
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if (len > 2)
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value += *bf++ << 16;
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if (len > 1)
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value += *bf++ << 8;
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if (len > 0)
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value += *bf;
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return value;
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}
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int dccp_parse_options(struct sock *sk, struct sk_buff *skb)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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#ifdef CONFIG_IP_DCCP_DEBUG
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const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
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"CLIENT rx opt: " : "server rx opt: ";
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#endif
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const struct dccp_hdr *dh = dccp_hdr(skb);
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const u8 pkt_type = DCCP_SKB_CB(skb)->dccpd_type;
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unsigned char *options = (unsigned char *)dh + dccp_hdr_len(skb);
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unsigned char *opt_ptr = options;
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const unsigned char *opt_end = (unsigned char *)dh +
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(dh->dccph_doff * 4);
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struct dccp_options_received *opt_recv = &dp->dccps_options_received;
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unsigned char opt, len;
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unsigned char *value;
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u32 elapsed_time;
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memset(opt_recv, 0, sizeof(*opt_recv));
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while (opt_ptr != opt_end) {
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opt = *opt_ptr++;
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len = 0;
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value = NULL;
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/* Check if this isn't a single byte option */
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if (opt > DCCPO_MAX_RESERVED) {
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if (opt_ptr == opt_end)
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goto out_invalid_option;
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len = *opt_ptr++;
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if (len < 3)
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goto out_invalid_option;
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/*
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* Remove the type and len fields, leaving
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* just the value size
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*/
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len -= 2;
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value = opt_ptr;
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opt_ptr += len;
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if (opt_ptr > opt_end)
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goto out_invalid_option;
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}
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switch (opt) {
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case DCCPO_PADDING:
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break;
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case DCCPO_NDP_COUNT:
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if (len > 3)
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goto out_invalid_option;
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opt_recv->dccpor_ndp = dccp_decode_value_var(value, len);
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dccp_pr_debug("%sNDP count=%d\n", debug_prefix,
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opt_recv->dccpor_ndp);
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break;
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case DCCPO_ACK_VECTOR_0:
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case DCCPO_ACK_VECTOR_1:
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if (pkt_type == DCCP_PKT_DATA)
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continue;
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if (dp->dccps_options.dccpo_send_ack_vector &&
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dccp_ackvec_parse(sk, skb, opt, value, len))
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goto out_invalid_option;
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break;
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case DCCPO_TIMESTAMP:
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if (len != 4)
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goto out_invalid_option;
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opt_recv->dccpor_timestamp = ntohl(*(u32 *)value);
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dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
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dccp_timestamp(sk, &dp->dccps_timestamp_time);
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dccp_pr_debug("%sTIMESTAMP=%u, ackno=%llu\n",
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debug_prefix, opt_recv->dccpor_timestamp,
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(unsigned long long)
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DCCP_SKB_CB(skb)->dccpd_ack_seq);
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break;
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case DCCPO_TIMESTAMP_ECHO:
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if (len != 4 && len != 6 && len != 8)
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goto out_invalid_option;
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opt_recv->dccpor_timestamp_echo = ntohl(*(u32 *)value);
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dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, ackno=%llu, ",
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debug_prefix,
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opt_recv->dccpor_timestamp_echo,
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len + 2,
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(unsigned long long)
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DCCP_SKB_CB(skb)->dccpd_ack_seq);
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if (len == 4)
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break;
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if (len == 6)
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elapsed_time = ntohs(*(u16 *)(value + 4));
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else
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elapsed_time = ntohl(*(u32 *)(value + 4));
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/* Give precedence to the biggest ELAPSED_TIME */
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if (elapsed_time > opt_recv->dccpor_elapsed_time)
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opt_recv->dccpor_elapsed_time = elapsed_time;
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break;
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case DCCPO_ELAPSED_TIME:
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if (len != 2 && len != 4)
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goto out_invalid_option;
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if (pkt_type == DCCP_PKT_DATA)
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continue;
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if (len == 2)
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elapsed_time = ntohs(*(u16 *)value);
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else
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elapsed_time = ntohl(*(u32 *)value);
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if (elapsed_time > opt_recv->dccpor_elapsed_time)
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opt_recv->dccpor_elapsed_time = elapsed_time;
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dccp_pr_debug("%sELAPSED_TIME=%d\n", debug_prefix,
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elapsed_time);
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break;
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/*
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* From draft-ietf-dccp-spec-11.txt:
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*
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* Option numbers 128 through 191 are for
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* options sent from the HC-Sender to the
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* HC-Receiver; option numbers 192 through 255
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* are for options sent from the HC-Receiver to
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* the HC-Sender.
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*/
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case 128 ... 191: {
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const u16 idx = value - options;
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if (ccid_hc_rx_parse_options(dp->dccps_hc_rx_ccid, sk,
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opt, len, idx,
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value) != 0)
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goto out_invalid_option;
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}
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break;
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case 192 ... 255: {
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const u16 idx = value - options;
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if (ccid_hc_tx_parse_options(dp->dccps_hc_tx_ccid, sk,
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opt, len, idx,
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value) != 0)
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goto out_invalid_option;
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}
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break;
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default:
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pr_info("DCCP(%p): option %d(len=%d) not "
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"implemented, ignoring\n",
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sk, opt, len);
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break;
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}
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}
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return 0;
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out_invalid_option:
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DCCP_INC_STATS_BH(DCCP_MIB_INVALIDOPT);
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DCCP_SKB_CB(skb)->dccpd_reset_code = DCCP_RESET_CODE_OPTION_ERROR;
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pr_info("DCCP(%p): invalid option %d, len=%d\n", sk, opt, len);
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return -1;
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}
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static void dccp_encode_value_var(const u32 value, unsigned char *to,
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const unsigned int len)
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{
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if (len > 3)
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*to++ = (value & 0xFF000000) >> 24;
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if (len > 2)
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*to++ = (value & 0xFF0000) >> 16;
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if (len > 1)
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*to++ = (value & 0xFF00) >> 8;
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if (len > 0)
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*to++ = (value & 0xFF);
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}
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static inline int dccp_ndp_len(const int ndp)
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{
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return likely(ndp <= 0xFF) ? 1 : ndp <= 0xFFFF ? 2 : 3;
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}
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void dccp_insert_option(struct sock *sk, struct sk_buff *skb,
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const unsigned char option,
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const void *value, const unsigned char len)
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{
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unsigned char *to;
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if (DCCP_SKB_CB(skb)->dccpd_opt_len + len + 2 > DCCP_MAX_OPT_LEN) {
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LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
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"%d option!\n", option);
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return;
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}
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DCCP_SKB_CB(skb)->dccpd_opt_len += len + 2;
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to = skb_push(skb, len + 2);
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*to++ = option;
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*to++ = len + 2;
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memcpy(to, value, len);
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}
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EXPORT_SYMBOL_GPL(dccp_insert_option);
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static void dccp_insert_option_ndp(struct sock *sk, struct sk_buff *skb)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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int ndp = dp->dccps_ndp_count;
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if (dccp_non_data_packet(skb))
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++dp->dccps_ndp_count;
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else
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dp->dccps_ndp_count = 0;
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if (ndp > 0) {
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unsigned char *ptr;
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const int ndp_len = dccp_ndp_len(ndp);
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const int len = ndp_len + 2;
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if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
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return;
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DCCP_SKB_CB(skb)->dccpd_opt_len += len;
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ptr = skb_push(skb, len);
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*ptr++ = DCCPO_NDP_COUNT;
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*ptr++ = len;
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dccp_encode_value_var(ndp, ptr, ndp_len);
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}
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}
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static inline int dccp_elapsed_time_len(const u32 elapsed_time)
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{
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return elapsed_time == 0 ? 0 : elapsed_time <= 0xFFFF ? 2 : 4;
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}
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void dccp_insert_option_elapsed_time(struct sock *sk,
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struct sk_buff *skb,
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u32 elapsed_time)
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{
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#ifdef CONFIG_IP_DCCP_DEBUG
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struct dccp_sock *dp = dccp_sk(sk);
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const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
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"CLIENT TX opt: " : "server TX opt: ";
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#endif
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const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
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const int len = 2 + elapsed_time_len;
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unsigned char *to;
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if (elapsed_time_len == 0)
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return;
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if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
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LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to "
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"insert elapsed time!\n");
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return;
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}
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DCCP_SKB_CB(skb)->dccpd_opt_len += len;
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to = skb_push(skb, len);
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*to++ = DCCPO_ELAPSED_TIME;
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*to++ = len;
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if (elapsed_time_len == 2) {
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const u16 var16 = htons((u16)elapsed_time);
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memcpy(to, &var16, 2);
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} else {
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const u32 var32 = htonl(elapsed_time);
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memcpy(to, &var32, 4);
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}
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dccp_pr_debug("%sELAPSED_TIME=%u, len=%d, seqno=%llu\n",
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debug_prefix, elapsed_time,
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len,
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(unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
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}
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EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
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void dccp_timestamp(const struct sock *sk, struct timeval *tv)
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{
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const struct dccp_sock *dp = dccp_sk(sk);
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do_gettimeofday(tv);
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tv->tv_sec -= dp->dccps_epoch.tv_sec;
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tv->tv_usec -= dp->dccps_epoch.tv_usec;
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while (tv->tv_usec < 0) {
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tv->tv_sec--;
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tv->tv_usec += USEC_PER_SEC;
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}
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}
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EXPORT_SYMBOL_GPL(dccp_timestamp);
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void dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
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{
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struct timeval tv;
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u32 now;
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dccp_timestamp(sk, &tv);
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now = timeval_usecs(&tv) / 10;
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/* yes this will overflow but that is the point as we want a
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* 10 usec 32 bit timer which mean it wraps every 11.9 hours */
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now = htonl(now);
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dccp_insert_option(sk, skb, DCCPO_TIMESTAMP, &now, sizeof(now));
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}
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EXPORT_SYMBOL_GPL(dccp_insert_option_timestamp);
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static void dccp_insert_option_timestamp_echo(struct sock *sk,
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struct sk_buff *skb)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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#ifdef CONFIG_IP_DCCP_DEBUG
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const char *debug_prefix = dp->dccps_role == DCCP_ROLE_CLIENT ?
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"CLIENT TX opt: " : "server TX opt: ";
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#endif
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struct timeval now;
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u32 tstamp_echo;
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u32 elapsed_time;
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int len, elapsed_time_len;
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unsigned char *to;
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dccp_timestamp(sk, &now);
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elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
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elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
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len = 6 + elapsed_time_len;
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if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN) {
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LIMIT_NETDEBUG(KERN_INFO "DCCP: packet too small to insert "
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"timestamp echo!\n");
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return;
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}
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DCCP_SKB_CB(skb)->dccpd_opt_len += len;
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to = skb_push(skb, len);
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*to++ = DCCPO_TIMESTAMP_ECHO;
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*to++ = len;
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tstamp_echo = htonl(dp->dccps_timestamp_echo);
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memcpy(to, &tstamp_echo, 4);
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to += 4;
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if (elapsed_time_len == 2) {
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const u16 var16 = htons((u16)elapsed_time);
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memcpy(to, &var16, 2);
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} else if (elapsed_time_len == 4) {
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const u32 var32 = htonl(elapsed_time);
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memcpy(to, &var32, 4);
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}
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dccp_pr_debug("%sTIMESTAMP_ECHO=%u, len=%d, seqno=%llu\n",
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debug_prefix, dp->dccps_timestamp_echo,
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len,
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(unsigned long long) DCCP_SKB_CB(skb)->dccpd_seq);
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dp->dccps_timestamp_echo = 0;
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dp->dccps_timestamp_time.tv_sec = 0;
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dp->dccps_timestamp_time.tv_usec = 0;
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}
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void dccp_insert_options(struct sock *sk, struct sk_buff *skb)
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{
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struct dccp_sock *dp = dccp_sk(sk);
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DCCP_SKB_CB(skb)->dccpd_opt_len = 0;
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if (dp->dccps_options.dccpo_send_ndp_count)
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dccp_insert_option_ndp(sk, skb);
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if (!dccp_packet_without_ack(skb)) {
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if (dp->dccps_options.dccpo_send_ack_vector &&
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dccp_ackvec_pending(dp->dccps_hc_rx_ackvec))
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dccp_insert_option_ackvec(sk, skb);
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if (dp->dccps_timestamp_echo != 0)
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dccp_insert_option_timestamp_echo(sk, skb);
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}
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if (dp->dccps_hc_rx_insert_options) {
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ccid_hc_rx_insert_options(dp->dccps_hc_rx_ccid, sk, skb);
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dp->dccps_hc_rx_insert_options = 0;
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}
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if (dp->dccps_hc_tx_insert_options) {
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ccid_hc_tx_insert_options(dp->dccps_hc_tx_ccid, sk, skb);
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dp->dccps_hc_tx_insert_options = 0;
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}
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/* XXX: insert other options when appropriate */
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if (DCCP_SKB_CB(skb)->dccpd_opt_len != 0) {
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/* The length of all options has to be a multiple of 4 */
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int padding = DCCP_SKB_CB(skb)->dccpd_opt_len % 4;
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if (padding != 0) {
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padding = 4 - padding;
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memset(skb_push(skb, padding), 0, padding);
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DCCP_SKB_CB(skb)->dccpd_opt_len += padding;
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}
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}
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}
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